InSSIDer Wi-Fi Network Scanner

I used to have NetStumbler for Wi-Fi network scanning but it doesn't run on Windows 7 OS. Its development seems to have stalled. The newer InSSIDer network scanner runs natively on this new OS. It's interface shows the detected Access Points' signal strength graph in two panes. Aside from 2.4 GHz , it is also able to scan the 5 GHz spectrum.

Overall, the software is very good and it's FREE. It is downloadable from http://www.metageek.net/.

Happy scanning!